Absorbent articles such as diapers, incontinence protectors and sanitary napkins are intended to receive and absorb body fluids such as urine and menstrual fluid. Of course, articles with different forms and sizes exist depending on the area of use and the amount of fluid the article must be able to absorb. For example, diapers for heavily incontinent adults are considerably larger and have greater absorption capacity than diapers for babies. Furthermore, in addition to the requirements for sufficient absorption capacity and leakage security, there is also a requirement that the diaper be comfortable to wear. For adult users it is also important that the articles are discreet and can be worn without being noticed under normal clothing. A further important criterion for absorbent articles intended for single use is that they do not take up too much space during storage, transport and in the package bought by the consumer.
In order to obtain a sanitary napkin which has a good fit, it is known to produce articles with a three-dimensionally formed, anatomically adapted form. Absorbent articles which comprise shape-stable stiff members are described in SEA-9604223-9 and SE-A-9604221-3. The shape-stabilising members, or forming members, are three-dimensionally formed members constructed from materials which resist wrinkling or flattening when they are subjected to forces from the user's body, for example when the user walks or sits on the article. Although the three-dimensional shape solves the problem of obtaining a good fit during use of the absorbent articles, three-dimensional absorbent articles entail considerable difficulties during manufacturing and storage. Three-dimensional parts are difficult to handle in a manufacturing process, for example when they have to be assembled to make an absorbent article.
EP 0 834 296 A1 concerns an absorbent article which is flat in dry condition but which expands on wetting to a pre-determined, three-dimensional profile. The absorbent article has an expanded layer, preferably a foam of regenerated cellulose, i.e. viscose foam. Furthermore, the absorbent article has a liquid-permeable surface material. The liquid-permeable surface material has pleats in dry condition, which pleats unfold on wetting so that the expanding layer can swell to several times its dry volume. However, a problem with such an article is that viscose foams are very soft after being wetted. A further problem with the known article is that viscose foams have an insufficient liquid-retaining ability.